BioPAX pathway converted from "Trafficking and processing of endosomal TLR" in the Reactome database.

Trafficking and processing of endosomal TLR

Mammalian TLR3, TLR7, TLR8, TLR9 are endosomal receptors that sense nucleic acids that have been released from endocytosed/phagocytosed bacteria, viruses or parasites. These TLRs have a ligand-recognition domain that faces the lumen of the endosome (which is topologically equivalent to the outside of the cell), a transmembrane domain, and a signaling domain that faces the cytosol.Under normal conditions, self nucleic acids are not recognized by TLRs due to multiple levels of regulation including receptor compartmentalization, trafficking and proteolytic processing (Barton GM et al 2006, Ewald SE et al 2008). At steady state TLR3, TLR7, TLR8, TLR9 reside primarily in the endoplasmic reticulum (ER), however, their activation by specific ligands only occurs within acidified endolysosomal compartments (Hacker H et al 1998, Funami K et al 2004, Gibbard RJ et al 2006). Several chaperon proteins associate with TLRs in the ER to provide efficient translocation to endolysosome. Upon reaching endolysosomal compartments the ectodomains of TLR7 and TLR9 are proteolytically cleaved by cysteine endoproteases. Both full-length and cleaved C-terminus of TLR9 bind CpG-oligodeoxynucleotides, however it has been proposed that only the processed receptor is functional. Although similar cleavage of TLR3 has been reported by Ewald et al 2011, other studies demonstrated that the N-terminal region of TLR3 ectodomain was implicated in ligand binding, thus TLR3 may function as a full-length receptor (Liu L et al 2008, Tokisue T et al 2008). There are no data on TLR8 processing, although the cell biology of TLR8 is probably similar to TLR9 and TLR7 (Gibbard RJ et al 2006, Wei T et al 2009).

Authored: Shamovsky, V, 2011-10-19Reviewed: Gillespie, ME, 2012-02-09Reviewed: Leifer, CA, Rose II, WA, 2012-02-28Edited: Shamovsky, V, 2012-02-19

TLR folding by chaperones GP96 and CNPY3

GP96 (also known as GRP94, HSP90b1), a paralogue of HSP90 in the endoplasmic reticulum, acts as a chaperone for some integrines and Toll-like receptors. Macrophages or B-cells from gp96 knockout mice have abrogated function of TLR2, 4, 5, 7 and 9, but not TLR3 (Yang Y et al 2007, Liu B and Li Z 2008, Staron M et al 2010). GP96 interacts with TLRs and integrines via its C-terminal hydrophobic domain, formed by residues 652-678 (Wu S et al 2012). GP96 functions as a V-shaped dimer in ATP-dependent manner, however it remains unclear how ATP hydrolysis-dependent conformational changes of GP96 are regulated (Li Z and Srivastava PK 1993).GP96 forms a complex with co-chaperone CNPY3, also known as PRAT4A. GP96-CNPY3 promotes the proper post-translational ectodomain folding of TLRs, but not TLR3 (Liu B et al 2010).

Authored: Shamovsky, V, 2011-10-19Reviewed: Gillespie, ME, 2012-02-09Reviewed: Leifer, CA, Rose II, WA, 2012-02-28Edited: Shamovsky, V, 2012-02-19

Reactome DB_ID: 211579

endoplasmic reticulum membraneGO0005789

ATP(4-) [ChEBI:30616]

ATP(4-)

Adenosine 5'-triphosphateatpATP

Reactomehttp://www.reactome.orgChEBI30616

Reactome DB_ID: 1678941

endoplasmic reticulum lumenGO0005788Apo-GP96 dimer [endoplasmic reticulum lumen]

Apo-GP96 dimer

Reactome DB_ID: 981545

UniProt:P14625 HSP90B1

HSP90B1

TRA1GRP94HSP90B1FUNCTION Molecular chaperone that functions in the processing and transport of secreted proteins (By similarity). When associated with CNPY3, required for proper folding of Toll-like receptors (By similarity). Functions in endoplasmic reticulum associated degradation (ERAD) (PubMed:18264092). Has ATPase activity (By similarity). May participate in the unfolding of cytosolic leaderless cargos (lacking the secretion signal sequence) such as the interleukin 1/IL-1 to facilitate their translocation into the ERGIC (endoplasmic reticulum-Golgi intermediate compartment) and secretion; the translocation process is mediated by the cargo receptor TMED10 (PubMed:32272059).SUBUNIT Homodimer; disulfide-linked. Component of an EIF2 complex at least composed of CELF1/CUGBP1, CALR, CALR3, EIF2S1, EIF2S2, HSP90B1 and HSPA5 (By similarity). Part of a large chaperone multiprotein complex comprising DNAJB11, HSP90B1, HSPA5, HYOU, PDIA2, PDIA4, PDIA6, PPIB, SDF2L1, UGGT1 and very small amounts of ERP29, but not, or at very low levels, CALR nor CANX. Interacts with AIMP1; regulates its retention in the endoplasmic reticulum. Interacts with OS9. Interacts with CNPY3. This interaction is disrupted in the presence of ATP (By similarity). Interacts with TLR4 and TLR9, but not with TLR3. Interacts with MZB1 in a calcium-dependent manner (By similarity). Interacts with METTL23. Interacts with IL1B; the interaction facilitates cargo translocation into the ERGIC (PubMed:32272059).SIMILARITY Belongs to the heat shock protein 90 family.

Homo sapiens

NCBI Taxonomy9606UniProtP14625

Chain Coordinates

EQUAL

803

EQUAL

Reactome Database ID Release 751678941Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678941ReactomeR-HSA-1678941

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678941.1

Reactome DB_ID: 1678932

UniProt:Q9BT09 CNPY3

CNPY3

CTG4APRAT4AHSPC084UNQ1934/PRO4409ERDA5CNPY3TNRC5FUNCTION Toll-like receptor (TLR)-specific co-chaperone for HSP90B1. Required for proper TLR folding, except that of TLR3, and hence controls TLR exit from the endoplasmic reticulum. Consequently, required for both innate and adaptive immune responses (By similarity).SUBUNIT Interacts with HSP90B1; this interaction is disrupted in the presence of ATP. Interacts with TLR1, TLR2, TLR4 and TLR9 (By similarity). Strongest interaction with TLR4 (By similarity).SIMILARITY Belongs to the canopy family.

UniProtQ9BT09

EQUAL

278

EQUAL

Converted from EntitySet in Reactome

Reactome DB_ID: 1679009

TLR7/8/9 [endoplasmic reticulum membrane]Converted from EntitySet in Reactome. Each synonym is a name of a PhysicalEntity, and each XREF points to one PhysicalEntityTLR9 [endoplasmic reticulum membrane]TLR7 [endoplasmic reticulum membrane]

UniProtQ9NR96UniProtQ9NYK1

Reactome DB_ID: 1679076

ATP-bound Gp96 dimer:CNPY3:TLR7/8/9 [endoplasmic reticulum membrane]

ATP-bound Gp96 dimer:CNPY3:TLR7/8/9

Reactome DB_ID: 211579

Reactome DB_ID: 981545

EQUAL

803

EQUAL

Reactome DB_ID: 1678932

EQUAL

278

EQUAL

Converted from EntitySet in Reactome

Reactome DB_ID: 1679009

Reactome Database ID Release 751679076Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1679076ReactomeR-HSA-1679076

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1679076.1Reactome Database ID Release 751678923Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678923ReactomeR-HSA-1678923

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678923.117275357Pubmed2007Heat shock protein gp96 is a master chaperone for toll-like receptors and is important in the innate function of macrophagesYang, YLiu, BDai, JSrivastava, PKZammit, DJLefrançois, LLi, ZImmunity 26:215-2618509083Pubmed2008Endoplasmic reticulum HSP90b1 (gp96, grp94) optimizes B-cell function via chaperoning integrin and TLR but not immunoglobulinLiu, BLi, ZBlood 112:1223-3022223641Pubmed2012The Molecular Chaperone gp96/GRP94 Interacts With Toll-Like Receptors And Integrins Via Its C-Terminal Hydrophobic DomainWu, SHong, FGewirth, DGuo, BLiu, BLi, ZJ Biol Chem8344253Pubmed1993Tumor rejection antigen gp96/grp94 is an ATPase: implications for protein folding and antigen presentationLi, ZSrivastava, PKEMBO J 12:3143-5119965672Pubmed2010gp96, an endoplasmic reticulum master chaperone for integrins and Toll-like receptors, selectively regulates early T and B lymphopoiesisStaron, MYang, YLiu, BLi, JShen, YZúñiga-Pflücker, JCAguila, HLGoldschneider, ILi, ZBlood 115:2380-9020865800Pubmed2010Folding of Toll-like receptors by the HSP90 paralogue gp96 requires a substrate-specific cochaperoneLiu, BYang, YQiu, ZStaron, MHong, FLi, YWu, SLi, YunfengHao, BBona, RHan, DLi, ZNat Commun 1:79

Folded full-length TLR7/8/9 dissociates from the GP96:CNPY3 complex

Folded TLR9 dissociates from GP96:CNPY3 complex (Liu B et al 2010) and translocates to the endolysosome with the aid of the membrane protein UNC93b. Here we assume that TLR7 and TLR8 behave in a similar manner.

Authored: Shamovsky, V, 2011-10-19Reviewed: Gillespie, ME, 2012-02-09Reviewed: Leifer, CA, Rose II, WA, 2012-02-28Edited: Shamovsky, V, 2012-02-19

Reactome DB_ID: 1679076

Reactome DB_ID: 1678941

Reactome DB_ID: 1678932

EQUAL

278

EQUAL

Converted from EntitySet in Reactome

Reactome DB_ID: 1679066

folded FL-TLR7/8/9 [endoplasmic reticulum membrane]Converted from EntitySet in Reactome. Each synonym is a name of a PhysicalEntity, and each XREF points to one PhysicalEntity

Reactome DB_ID: 211606

ADP(3-) [ChEBI:456216]

ADP(3-)

ADP trianion5'-O-[(phosphonatooxy)phosphinato]adenosineADP

ChEBI456216Reactome Database ID Release 751678944Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678944ReactomeR-HSA-1678944

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678944.1

Full-length TLR3/7/8/9 binds to UNC93B1

Mammalian UNC93B1, a multi-transmembrane protein, directly associates with transmembrane domains of TLR3, TLR7, TLR8 and TLR9 (and mouse TLR13) in the ER and facilitates their translocation to endolysosome compartments (Brinkmann et al 2007; Kim et al 2008; Itoh H et al 2011). Mutant mouse and human cells that lack functional UNC93B1 showed disrupted signaling via the endosomal TLRs (Taneda K et al 2006; Fukui et al 2009; Kim YM et al 2008; Qi R et al 2010; Koehn J et al 2007). Furthermore, defects in the human gene encoding UNC93B1 are associated with the increased susceptibility to herpes simplex encephalitis (HSE) in children (Casrouge A et al 2006).TLR7 and TLR9 compete for UNC931-dependent trafficking and under normal circumstances TLR9 predominates over TLR7. This preference for TLR9 is mediated by an N-terminal domain in UNC93B1 and is reversed to TLR7 if UNC93B1 loses the preferential N-terminal binding site via mutation of aspartate at position 34. Loss of binding to TLR9 and preferential association with TLR7 resulted in hyperresponsiveness to RNA ligands (Fukui et al 2009).TLR3 appears to translocate to the endosomal compartment with equal efficiency regardless of the presence or absence of the N-terminal domain that mediates preference for TLR9. Thus, endosomal TLR trafficking is orchestrated by UNC93B1 which determines how efficiently each TLR is able to move from the ER to the endolysosomes to initiate host responses.

Authored: Shamovsky, V, 2011-10-19Reviewed: Gillespie, ME, 2012-02-09Reviewed: Leifer, CA, Rose II, WA, 2012-02-28Edited: Shamovsky, V, 2012-02-19

Converted from EntitySet in Reactome

Reactome DB_ID: 1679054

intracellular TLR3/7/8/9 [endoplasmic reticulum membrane]Converted from EntitySet in Reactome. Each synonym is a name of a PhysicalEntity, and each XREF points to one PhysicalEntityTLR3 [endoplasmic reticulum membrane]

UniProtO15455

Reactome DB_ID: 1678930

UniProt:Q9H1C4 UNC93B1

UNC93B1

UNC93B1UNC93UNC93BFUNCTION Plays an important role in innate and adaptive immunity by regulating nucleotide-sensing Toll-like receptor (TLR) signaling. Required for the transport of a subset of TLRs (including TLR3, TLR7 and TLR9) from the endoplasmic reticulum to endolysosomes where they can engage pathogen nucleotides and activate signaling cascades. May play a role in autoreactive B-cells removal.SUBUNIT Interacts with TLR3, TLR5, TLR7, and TLR9 (probably via transmembrane domain).TISSUE SPECIFICITY Expressed in plasmocytoid dendritic cells (at protein level). Highly expressed in antigen-presenting cells. Expressed in heart, and at lower level in kidney. Expressed at low level in other tissues.INDUCTION Up-regulated by TLRs agonists.PTM N-glycosylated.SIMILARITY Belongs to the unc-93 family.

UniProtQ9H1C4

EQUAL

597

EQUAL

Reactome DB_ID: 1678926

intracellular TLR:UNC93B1 [endoplasmic reticulum membrane]

intracellular TLR:UNC93B1

Converted from EntitySet in Reactome

Reactome DB_ID: 1679054

Reactome DB_ID: 1678930

EQUAL

597

EQUAL

Reactome Database ID Release 751678926Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678926ReactomeR-HSA-1678926

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678926.1Reactome Database ID Release 751678921Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678921ReactomeR-HSA-1678921

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678921.116415873Pubmed2006The Unc93b1 mutation 3d disrupts exogenous antigen presentation and signaling via Toll-like receptors 3, 7 and 9Tabeta, KHoebe, KJanssen, EMDu, XGeorgel, PCrozat, KMudd, SMann, NSovath, SGoode, JShamel, LHerskovits, AAPortnoy, DACooke, MTarantino, LMWiltshire, TSteinberg, BEGrinstein, SBeutler, BNat Immunol 7:156-6419451267Pubmed2009Unc93B1 biases Toll-like receptor responses to nucleic acid in dendritic cells toward DNA- but against RNA-sensingFukui, RSaitoh, SMatsumoto, FKozuka-Hata, HOyama, MTabeta, KBeutler, BMiyake, KJ Exp Med 206:1339-5018082565Pubmed2007Assessing the function of human UNC-93B in Toll-like receptor signaling and major histocompatibility complex II responseKoehn, JHuesken, DJaritz, MRot, AZurini, MDwertmann, ABeutler, BKorthäuer, UHum Immunol 68:871-817452530Pubmed2007The interaction between the ER membrane protein UNC93B and TLR3, 7, and 9 is crucial for TLR signalingBrinkmann, MMSpooner, EHoebe, KBeutler, BPloegh, HLKim, YMJ Cell Biol 177:265-7518305481Pubmed2008UNC93B1 delivers nucleotide-sensing toll-like receptors to endolysosomesKim, YMBrinkmann, MMPaquet, MEPloegh, HLNature 452:234-820855885Pubmed2010Secretion of the human Toll-like receptor 3 ectodomain is affected by single nucleotide polymorphisms and regulated by Unc93b1Qi, RHoose, SSchreiter, JSawant, KVLamb, RRanjith-Kumar, CTMills, JSan Mateo, LJordan, JLKao, CCJ Biol Chem 285:36635-4416973841Pubmed2006Herpes simplex virus encephalitis in human UNC-93B deficiencyCasrouge, AZhang, SYEidenschenk, CJouanguy, EPuel, AYang, KAlcais, APicard, CMahfoufi, NNicolas, NLorenzo, LPlancoulaine, SSénéchal, BGeissmann, FTabeta, KHoebe, KDu, XMiller, RLHéron, BMignot, Cde Villemeur, TBLebon, PierreDulac, ORozenberg, FBeutler, BTardieu, MAbel, LCasanova, JLScience 314:308-1222164301Pubmed2011UNC93B1 physically associates with human TLR8 and regulates TLR8-mediated signalingItoh, HirokiTatematsu, MegumiWatanabe, AyakoIwano, KatsunoriFunami, KSeya, TMatsumoto, MPLoS ONE 6:e28500

Endosomal TLRs pass through the Golgi

TLRs traffic through the Golgi complex by the conventional secretory pathway and are routed to endolysosomes where they bind their ligands (Chockalingam A et al 2008, Ewald SE et al 2011). .

Authored: Shamovsky, V, 2011-10-19Reviewed: Gillespie, ME, 2012-02-09Reviewed: Leifer, CA, Rose II, WA, 2012-02-28Edited: Shamovsky, V, 2012-02-19

Reactome DB_ID: 1678926

Reactome DB_ID: 1679067

Golgi membraneGO0000139intracellular TLR:UNC93B1 [Golgi membrane]

intracellular TLR:UNC93B1

Converted from EntitySet in Reactome

Reactome DB_ID: 1679038

TLR3/7/8/9 [Golgi membrane]Converted from EntitySet in Reactome. Each synonym is a name of a PhysicalEntity, and each XREF points to one PhysicalEntityTLR3 [Golgi membrane]

Reactome DB_ID: 1679064

EQUAL

597

EQUAL

Reactome Database ID Release 751679067Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1679067ReactomeR-HSA-1679067

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1679067.1Reactome Database ID Release 751678998Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678998ReactomeR-HSA-1678998

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678998.121402738Pubmed2011Nucleic acid recognition by Toll-like receptors is coupled to stepwise processing by cathepsins and asparagine endopeptidaseEwald, SEEngel, ALee, JWang, MBogyo, MBarton, GMJ Exp Med 208:643-5119079358Pubmed2009TLR9 traffics through the Golgi complex to localize to endolysosomes and respond to CpG DNAChockalingam, ABrooks, JCCameron, JLBlum, LKLeifer, CAImmunol Cell Biol 87:209-17

UNC93B1 delivers endosomal full-length TLRs to endolysosome

TLR3, 7, 8 and 9 activation occurs within acidified endolysosomal compartments. Inhibition of endosome acidification with bafilomicin A or chloroquine abrogated TLR's-mediated responses to pathogen-derived nucleic acids (Hacker H et al 1998, Funami K et al 2004, Gibbard RJ et al 2006, Kuznik A et al 2011). Upon stimulation, TLR3, 7, and 9 (and possibly TLR8) are transported to the signaling endosomes by UNC93B1, whereby they become functional receptors and bind to their specific ligands (Kim et al 2008, Ewald et al 2011). Although UNC93B1 is critically involved in TLRs trafficking it was dispensable for ligand binding by these TLRs (Kim YM et al 2008).

Authored: Shamovsky, V, 2011-10-19Reviewed: Gillespie, ME, 2012-02-09Reviewed: Leifer, CA, Rose II, WA, 2012-02-28Edited: Shamovsky, V, 2012-02-19

Reactome DB_ID: 1679067

Reactome DB_ID: 188168

endolysosome membraneGO0036020FL-TLR7 dimer [endolysosome membrane]

FL-TLR7 dimer

Reactome DB_ID: 168005

UniProt:Q9NYK1 TLR7

TLR7

TLR7UNQ248/PRO285FUNCTION Endosomal receptor that plays a key role in innate and adaptive immunity (PubMed:14976261, PubMed:32433612). Controls host immune response against pathogens through recognition of uridine-containing single strand RNAs (ssRNAs) of viral origin or guanosine analogs (PubMed:31608988, PubMed:27742543, PubMed:12738885). Upon binding to agonists, undergoes dimerization that brings TIR domains from the two molecules into direct contact, leading to the recruitment of TIR-containing downstream adapter MYD88 through homotypic interaction (PubMed:27742543). In turn, the Myddosome signaling complex is formed involving IRAK4, IRAK1, TRAF6, TRAF3 leading to activation of downstream transcription factors NF-kappa-B and IRF7 to induce proinflammatory cytokines and interferons, respectively (PubMed:27742543).ACTIVITY REGULATION Activated by guanosine analogs including deoxyguanosine, 7-thia-8-oxoguanosine or 7-deazaguanosine in a RNA-independent manner.SUBUNIT Homodimer (PubMed:27742543). Interacts with MYD88 via their respective TIR domains (Probable). Interacts with UNC93B1 (By similarity). Interacts with SMPDL3B (By similarity).TISSUE SPECIFICITY Detected in brain, placenta, spleen, stomach, small intestine, lung and in plasmacytoid pre-dendritic cells.DOMAIN Contains two binding domains, first site for small ligands and second site for ssRNA.SIMILARITY Belongs to the Toll-like receptor family.

EQUAL

1049

EQUAL

Reactome Database ID Release 75188168Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=188168ReactomeR-HSA-188168

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-188168.1

Reactome DB_ID: 1679073

FL-TLR9 dimer [endolysosome membrane]

FL-TLR9 dimer

full-length TLR9 dimer

Reactome DB_ID: 167979

UniProt:Q9NR96 TLR9

TLR9

TLR9UNQ5798/PRO19605FUNCTION Key component of innate and adaptive immunity. TLRs (Toll-like receptors) control host immune response against pathogens through recognition of molecular patterns specific to microorganisms. TLR9 is a nucleotide-sensing TLR which is activated by unmethylated cytidine-phosphate-guanosine (CpG) dinucleotides. Acts via MYD88 and TRAF6, leading to NF-kappa-B activation, cytokine secretion and the inflammatory response (PubMed:11564765, PubMed:17932028). Controls lymphocyte response to Helicobacter infection (By similarity). Upon CpG stimulation, induces B-cell proliferation, activation, survival and antibody production (PubMed:23857366).SUBUNIT Monomer and homodimer. Exists as a monomer in the absence of unmethylated cytidine-phosphate-guanosine (CpG) ligand. Proteolytic processing of an insertion loop (Z-loop) is required for homodimerization upon binding to the unmethylated CpG ligand leading to its activation (By similarity). Interacts with MYD88 via their respective TIR domains (By similarity). Interacts with BTK (PubMed:17932028). Interacts (via transmembrane domain) with UNC93B1. Interacts with CD300LH; the interaction may promote full activation of TLR9-triggered innate responses (By similarity). Interacts with CNPY3 and HSP90B1; this interaction is required for proper folding in the endoplasmic reticulum (PubMed:20865800). Interacts with SMPDL3B (By similarity).TISSUE SPECIFICITY Highly expressed in spleen, lymph node, tonsil and peripheral blood leukocytes, especially in plasmacytoid pre-dendritic cells. Levels are much lower in monocytes and CD11c+ immature dendritic cells. Also detected in lung and liver.PTM Activated by proteolytic cleavage of the flexible loop between repeats LRR14 and LRR15 within the ectodomain. Cleavage requires UNC93B1. Proteolytically processed by first removing the majority of the ectodomain by either asparagine endopeptidase (AEP) or a cathepsin followed by a trimming event that is solely cathepsin mediated and required for optimal receptor signaling.SIMILARITY Belongs to the Toll-like receptor family.

EQUAL

1032

EQUAL

Reactome Database ID Release 751679073Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1679073ReactomeR-HSA-1679073

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1679073.1

Reactome DB_ID: 167941

UniProt:O15455 TLR3

TLR3

TLR3FUNCTION Key component of innate and adaptive immunity. TLRs (Toll-like receptors) control host immune response against pathogens through recognition of molecular patterns specific to microorganisms. TLR3 is a nucleotide-sensing TLR which is activated by double-stranded RNA, a sign of viral infection. Acts via the adapter TRIF/TICAM1, leading to NF-kappa-B activation, IRF3 nuclear translocation, cytokine secretion and the inflammatory response.SUBUNIT Monomer and homodimer; dimerization is triggered by ligand-binding, the signaling unit is composed of one ds-RNA of around 40 bp and two TLR3 molecules, and lateral clustering of signaling units along the length of the ds-RNA ligand is required for TLR3 signal transduction. Interacts (via transmembrane domain) with UNC93B1; the interaction is required for transport from the ER to the endosomes. Interacts with SRC; upon binding of double-stranded RNA. Interacts with TICAM1 (via the TIR domain) in response to poly(I:C) and this interaction is enhanced in the presence of WDFY1 (PubMed:25736436). The tyrosine-phosphorylated form (via TIR domain) interacts with WDFY1 (via WD repeat 2) in response to poly(I:C) (PubMed:25736436).TISSUE SPECIFICITY Expressed at high level in placenta and pancreas. Also detected in CD11c+ immature dendritic cells. Only expressed in dendritic cells and not in other leukocytes, including monocyte precursors. TLR3 is the TLR that is expressed most strongly in the brain, especially in astrocytes, glia, and neurons.DOMAIN ds-RNA binding is mediated by LRR 1 to 3, and LRR 17 to 18.PTM Heavily N-glycosylated, except on that part of the surface of the ectodomain that is involved in ligand binding.PTM TLR3 signaling requires a proteolytic cleavage mediated by cathepsins CTSB and CTSH, the cleavage occurs between amino acids 252 and 346. The cleaved form of TLR3 is the predominant form found in endosomes.POLYMORPHISM The Phe-412 allele (dbSNP:rs3775291) occurs with a frequency of 30% in populations with European and Asian ancestry, and confers some natural resistance to HIV-1 infection.SIMILARITY Belongs to the Toll-like receptor family.

EQUAL

904

EQUAL

Reactome DB_ID: 1679064

EQUAL

597

EQUAL

Reactome DB_ID: 188165

TLR8 dimer [endolysosome membrane]

TLR8 dimer

full length TLR8

Reactome DB_ID: 167927

UniProt:Q9NR97 TLR8

TLR8

UNQ249/PRO286TLR8FUNCTION Endosomal receptor that plays a key role in innate and adaptive immunity (PubMed:25297876, PubMed:32433612). Controls host immune response against pathogens through recognition of RNA degradation products specific to microorganisms that are initially processed by RNASET2 (PubMed:31778653). Upon binding to agonists, undergoes dimerization that brings TIR domains from the two molecules into direct contact, leading to the recruitment of TIR-containing downstream adapter MYD88 through homotypic interaction (PubMed:23520111, PubMed:25599397, PubMed:26929371). In turn, the Myddosome signaling complex is formed involving IRAK4, IRAK1, TRAF6, TRAF3 leading to activation of downstream transcription factors NF-kappa-B and IRF7 to induce proinflammatory cytokines and interferons, respectively (PubMed:16737960, PubMed:17932028, PubMed:29155428).ACTIVITY REGULATION Activated by RNAs having enough uridines.SUBUNIT Homodimer (PubMed:23520111, PubMed:25599397, PubMed:26929371, PubMed:29155428). Interacts with MYD88 via their respective TIR domains (Probable). Interacts with UNC93B1 (By similarity). Interacts with BTK (PubMed:17932028). Interacts with SMPDL3B (By similarity).TISSUE SPECIFICITY Expressed in myeloid dendritic cells, monocytes, and monocyte-derived dendritic cells.PTM Ubiquitinated by RNF216; leading to degradation by the proteasome.PTM Proteolytic processing occurs in monocytes and monocyte-derived macrophages by both furin-like proprotein convertase and cathepsins (PubMed:25297876). The cleavage is necessary for dimer formation and subsequent activation (PubMed:26929371).SIMILARITY Belongs to the Toll-like receptor family.

UniProtQ9NR97

EQUAL

1041

EQUAL

Reactome Database ID Release 75188165Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=188165ReactomeR-HSA-188165

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-188165.1Reactome Database ID Release 751678927Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678927ReactomeR-HSA-1678927

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678927.115226270Pubmed2004The cytoplasmic 'linker region' in Toll-like receptor 3 controls receptor localization and signalingFunami, KMatsumoto, MOshiumi, HAkazawa, TYamamoto, ASeya, TInt Immunol 16:1143-549799232Pubmed1998CpG-DNA-specific activation of antigen-presenting cells requires stress kinase activity and is preceded by non-specific endocytosis and endosomal maturationHacker, HMischak, HMiethke, TLiptay, SSchmid, RSparwasser, THeeg, KLipford, GBWagner, HEMBO J 17:6230-4016857668Pubmed2006Conserved features in the extracellular domain of human toll-like receptor 8 are essential for pH-dependent signalingGibbard, RJMorley, PJGay, Nicholas JJ Biol Chem 281:27503-1121398612Pubmed2011Mechanism of endosomal TLR inhibition by antimalarial drugs and imidazoquinolinesKuznik, ABencina, MSvajger, UJeras, MRozman, BJerala, RJ Immunol 186:4794-80414716310Pubmed2004TLR9 signals after translocating from the ER to CpG DNA in the lysosomeLatz, ESchoenemeyer, AVisintin, AFitzgerald, Katherine AMonks, BGKnetter, CFLien, ENilsen, NJEspevik, TGolenbock, DTNat Immunol 5:190-8

3.4.22

TLR processing at low pH

Endosome maturation (acidification) is required for both the activation of TLR9 and TLR7 through proteolytic cleavage and the disassembly of pathogens, thereby releasing the TLR ligands within them. TLR7 and TLR9 are cleaved within their ectodomains by pH-sensitive cysteine endopeptidases. Cathepsins (CTS) B, K, L, and S, and asparagine endopeptidase (AEP, also known as legumain) have been implicated in endolysosomal TLR processing, however, several groups have reported somewhat controversial results on the role of specific proteases (Matsumoto F et al 2008, Park B et al 2008, Ewald SE et al 2008, Ewald SE et al 2011, Sepulveda FE et al 2009).One study showed that TLR9 proteolysis is a multistep process with the initial cleavage that can be mediated by AEP or multiple members of the cathepsin family. The second event is mediated exclusively by cathepsins. TLR7 and TLR3 were reported to be cleaved in a similar manner (Ewald SE et al 2011). Cleavage of TLR3 is not shown in this reaction, since other studies demonstrated that the N-terminal region of TLR3 ectodomain was implicated in ligand binding, suggesting that TLR3 may function as a full-length receptor (Liu L et al 2008, Tokisue T et al 2008). Both full-length receptor and cleaved fragment corresponding to the C-terminal part of TLR9 were capable to bind ligand, however only the processed form (TLR9 C-ter, aa 471-1032) was shown to bind MyD88 and induce signaling in different mouse cells (Ewald SE et al 2008).

Authored: Shamovsky, V, 2011-10-19Reviewed: Gillespie, ME, 2012-02-09Reviewed: Leifer, CA, Rose II, WA, 2012-02-28Edited: Shamovsky, V, 2012-02-19

Reactome DB_ID: 188168

Reactome DB_ID: 1679073

Reactome DB_ID: 1678924

C-ter TLR7 dimer [endolysosome membrane]

C-ter TLR7 dimer

C-terminus TLR7 dimer

Reactome DB_ID: 1679027

EQUAL

1049

EQUAL

Reactome Database ID Release 751678924Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678924ReactomeR-HSA-1678924

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678924.1

Reactome DB_ID: 1678956

C-ter-TLR9 dimer [endolysosome membrane]

C-ter-TLR9 dimer

C-terminus Toll like receptor 9 (TLR9) dimer

Reactome DB_ID: 1678982

EQUAL

1032

EQUAL

Reactome Database ID Release 751678956Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678956ReactomeR-HSA-1678956

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678956.1PHYSIOL-LEFT-TO-RIGHT

ACTIVATION

Converted from EntitySet in Reactome

Reactome DB_ID: 1678911

endolysosome lumenGO0036021

Legumain/Cathepsins [endolysosome lumen]Converted from EntitySet in Reactome. Each synonym is a name of a PhysicalEntity, and each XREF points to one PhysicalEntityCTSB(80-333) [endolysosome lumen]CTSS [endolysosome lumen]CTSK [endolysosome lumen]LGMN [endolysosome lumen]

UniProtP07858UniProtP25774UniProtP43235UniProtQ99538GO0004197

GO molecular function

Reactome Database ID Release 751678966Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678966Reactome Database ID Release 751678920Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678920ReactomeR-HSA-1678920

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678920.218166152Pubmed2008Cathepsins are required for Toll-like receptor 9 responsesMatsumoto, FSaitoh, SFukui, RKobayashi, TTanimura, NKonno, KKusumoto, YAkashi-Takamura, SMiyake, KBiochem Biophys Res Commun 367:693-918820679Pubmed2008The ectodomain of Toll-like receptor 9 is cleaved to generate a functional receptorEwald, SELee, BLLau, LWickliffe, KEShi, GPChapman, HABarton, GMNature 456:658-6218931679Pubmed2008Proteolytic cleavage in an endolysosomal compartment is required for activation of Toll-like receptor 9Park, BBrinkmann, MMSpooner, ELee, CCKim, YMPloegh, HLNat Immunol 9:1407-14

ACTIVATION

Reactome Database ID Release 752134525Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=2134525ReactomeR-HSA-2134525

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-2134525.1

Reactome DB_ID: 9631150

hydron [ChEBI:15378]

hydron

ChEBI15378

3.4.22

TLR9 processing at neutral pH

TLR9 traffics to an endosomal vesicle where it is processed by cathepsin S at neural pH to generate an N-terminal product (TLR9 N-ter, aa 1-723). The N-terminal fragment of TLR9 also binds ligand, but in contrast to the C-terminal fragment it inhibits TLR9 signaling. Thus, a proper balance between the two proteolytic events probably regulates TLR9-mediated host responses. (Chockalingam A et al 2011).

Authored: Shamovsky, V, 2011-10-19Reviewed: Gillespie, ME, 2012-02-09Reviewed: Leifer, CA, Rose II, WA, 2012-02-28Edited: Shamovsky, V, 2012-02-19

Reactome DB_ID: 1679073

Reactome DB_ID: 1679007

N-ter TLR9 dimer [endolysosome membrane]

N-ter TLR9 dimer

Reactome DB_ID: 1679032

Reactome Database ID Release 751679007Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1679007ReactomeR-HSA-1679007

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1679007.1PHYSIOL-LEFT-TO-RIGHT

ACTIVATION

Converted from EntitySet in Reactome

Reactome DB_ID: 4127476

CTSS-like proteins [endolysosome lumen]Converted from EntitySet in Reactome. Each synonym is a name of a PhysicalEntity, and each XREF points to one PhysicalEntityCTSS [endolysosome lumen]

Reactome Database ID Release 751678988Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678988Reactome Database ID Release 751678981Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1678981ReactomeR-HSA-1678981

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1678981.121604257Pubmed2011Negative regulation of signaling by a soluble form of toll-like receptor 9Chockalingam, ACameron, JLBrooks, JCLeifer, CAEur J Immunol 41:2176-84

Reactome Database ID Release 751679131Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=1679131ReactomeR-HSA-1679131

Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-1679131.116144834Pubmed2005Recognition of double-stranded RNA by human toll-like receptor 3 and downstream receptor signaling requires multimerization and an acidic pHde Bouteiller, OMerck, EHasan, UAHubac, SBenguigui, BTrinchieri, GBates, EECaux, CJ Biol Chem 280:38133-4519521997Pubmed2009Homology modeling of human Toll-like receptors TLR7, 8, and 9 ligand-binding domainsWei, TGong, JJamitzky, FHeckl, WMStark, RWRössle, SCProtein Sci 18:1684-9116341217Pubmed2006Intracellular localization of Toll-like receptor 9 prevents recognition of self DNA but facilitates access to viral DNABarton, GMKagan, JCMedzhitov, RNat Immunol 7:49-5618776324Pubmed2008Significance of the N-terminal histidine-rich region for the function of the human toll-like receptor 3 ectodomainTokisue, TWatanabe, TTsujita, TNishikawa, SHasegawa, TSeya, TMatsumoto, MFukuda, KNucleic Acids Symp Ser (Oxf)203-418420935Pubmed2008Structural basis of toll-like receptor 3 signaling with double-stranded RNALiu, LBotos, IWang, YLeonard, JNShiloach, JSegal, DMDavies, DRScience 320:379-81